As defined by wikipedia. http://en.wikipedia.org/wiki/Mass_customization [1]
Mass customization, in marketing, manufacturing, and management, is the use of flexible computer-aided manufacturing systems to produce custom output. Those systems combine the low unit costs of mass production processes with the flexibility of individual customization.
The concept of mass customization is attributed to Stan Davis in Future Perfect [1] and was defined by Tseng and Jiao (2001, p. 685) as "producing goods and services to meet individual customer's needs with near mass production efficiency". Kaplan and Haenlein (2006, pp. 168-182) concurred, calling it "a strategy that creates value by some form of company-customer interaction at the fabrication / assembly stage of the operations level to create customized products with production cost and monetary price similar to those of mass-produced products".